> ## Documentation Index
> Fetch the complete documentation index at: https://docs.realtimelca.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Assumptions and defaults

> The default values Real-Time LCA uses for reference study period, transport, construction waste, end-of-life scenarios, and reference service life — and where you can override them.

Every Real-Time LCA calculation runs against a set of default assumptions for values not supplied by the underlying EPD. This page lists the defaults, their source, and where on a project they can be overridden.

## Reference study period

The reference study period (RSP) is the lifespan over which a building's whole-life impacts are evaluated.

* **Default:** **50 years** for every regulatory calculation type — BR18 (all variants), TEK17, Klimatdeklaration, Climate Declaration (2026–2028 and 2029), HMS, QNG (all tiers), IGBC WLC, and Level(s).
* **Custom calculation type:** the RSP is not fixed and can be set per project.

The 50-year RSP drives module B4 (replacement) calculations: any construction product whose reference service life is shorter than the RSP will be replaced one or more times within the study period.

## Reference Service Life

Reference Service Life (RSL) is the expected lifetime of an individual construction product before replacement. Real-Time LCA reads RSL values from:

* **National lifetime tables** — for example the BR18 lifetime table for Denmark, equivalents for Norway and other supported countries.
* **EPD-declared service life** — where the EPD provides an authoritative value, it takes precedence over the national default.
* **User override** — RSL can be overridden per component on any project.

## Transport (A4)

Module A4 covers transport from the factory gate to the construction site.

* **Default distances:** per region and material category, derived from authoritative regulatory references where available (e.g. BR18 default A4 distances for Danish projects).
* **Default transport modes:** road truck is the standard default; modes for sea and rail freight are configurable for specific routes.
* **Override:** per inventory item, on a project.

## Construction waste (A5)

Module A5 covers the construction and installation process, including waste arising from cutting and installation.

* **Default waste factors:** per material category, expressed as a percentage of the installed quantity.
* **Override:** per inventory item, on a project.

## End-of-life scenarios (C3, C4)

Modules C3 (waste pretreatment) and C4 (disposal) require a country-specific end-of-life scenario per material category.

* **Defaults:** country-specific scenarios reflecting typical recycling, energy recovery, and landfill shares for each material category. These differ between Denmark, Norway, Sweden, Finland, Germany, and other supported countries.
* **Override:** per inventory item, on a project, when the project's actual end-of-life route differs from the country default.

## Operational energy (B6)

Module B6 (energy consumption for operation) depends on:

* **Energy demand** — user-supplied per energy carrier (electricity, district heating, gas, oil, etc.) per project.
* **Carbon intensity per energy carrier** — country-specific default values updated periodically.
* **Override:** per energy carrier, on a project, to model a specific supplier mix or a forward-looking grid decarbonisation curve.

## Building-type thresholds (Denmark BR18 2025 and Low emission 2025)

For Danish projects on the BR18 (2025) or Low emission (2025) calculation types, the regulatory limit is **per-building-type** rather than a single value. Real-Time LCA carries the published per-building-type threshold table; the threshold applied to a project is determined by the building type selected on the project.

A separate **installation threshold** applies to construction-stage emissions (modules A4 + A5) under those calculation types. See [Denmark](/methodology-and-compliance/national-compliance/denmark).

## Where to find defaults in the platform

* **Project assumptions panel** — the project-level defaults (RSP, energy intensities, transport overrides).
* **Material library** — RSL and per-EPD declared values; see [Browse materials](/user-guide/library/materials/browse-materials).
* **Inventory item detail** — per-inventory-item overrides for transport, waste, and end-of-life route.

## Limitations

* This page describes the structure of default-and-override; the specific numeric defaults (transport distances per region, waste factors per material category, EOL splits per country) are maintained inside the platform and surfaced through the project assumptions panel, not duplicated here.
* Changes to platform defaults do not retroactively change past reports — see [Data quality](/methodology-and-compliance/data-quality) for reproducibility behaviour.